Effect of complex climatic environment on pore structure andmechanical properties of concrete(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2020年2期
- Page:
- 30-37
- Research Field:
- 道路工程
- Publishing date:
Info
- Title:
- Effect of complex climatic environment on pore structure andmechanical properties of concrete
- Author(s):
- CHEN Huaxin1; WANG Tong1; HE Rui1; 2; ZHANG Jiansong2; FANG Jianhong3; BAI Yonghou4
- (1. School of Materials Science and Engineering, Changan University, Xian 710061, Shaanxi, China;2. School of Construction Management Technology, Purdue University, West Lafayette IN 47907, Indiana, USA;3. Qinghai Academy of Transportation Sciences, Xining 810008, Qinghai, China; 4. CCCCSHEC FourthHighway Engineering CO., LTD., Luoyang 471013, Henan, China)
- Keywords:
- road engineering; concrete; low air pressure; dry; low temperature; pore structure; compressive strength
- PACS:
- -
- DOI:
- -
- Abstract:
- In order to study the influence of the plateau environment on concrete pore structure and mechanical properties, the airentrained concrete formed and cured in the plateau and plain regions was taken as the research object. Concrete formed and cured under different environments was used to analyze the porosity characteristic parameters of concrete, using a hardened concrete porosity analyzer after some cutting and surface treatments, and the 28 d compressive strength of concrete under different forming and curing environments was tested. The effects of different environments on concrete pore structure and mechanical properties were discussed. The influences of lowpressure, dry and lowtemperature environment on air content, average pore size, pore size distribution, pore spacing factor and 28 d compressive strength were obtained through comparative analysis. The relationship between the concrete pore structure and the compressive strength was established, and the reason for the deterioration of concrete pore structure and mechanical properties under the plateau environment was revealed. The results show that compared with the concrete cured at normal pressure, the air content of the hardened concrete cured under lowpressure standard reduced by 5% to 22%, the average pore size reduced by 2% to 5%, the spacing factor increased by 4% to 11%, and the strength increased by 5% to 10%. Compared with concrete cured under low air pressure, the air content of hardened concrete cured under plateau environment increased by 20% to 30%, the average pore diameter increased by 8% to 12%, and the spacing factor decreased by 15 to 20%, and the strength reduced by up to 36%. The dry and lowtemperature environment in the plateau area will affect the progress of the cement hydration reaction. The internal concrete structure will be loose and the porosity structure is deteriorated. At the same time, the frost heaving stress generated inside the concrete under lowtemperature environment lead to the damage to its structure and the decline of strength in the later period. Adding airentraining agent will increase the porosity in the concrete and reduce the strength, but the introduction of air bubbles in the plateau environment can effectively buffer the frost heave stress, and reduce the damage of the internal structure of the concrete and the loss of strength. 7 tabs, 6 figs, 25 refs.
Last Update: 2020-04-09